From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:42075 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755742Ab1BORbg (ORCPT ); Tue, 15 Feb 2011 12:31:36 -0500 Received: by yxt3 with SMTP id 3so199069yxt.19 for ; Tue, 15 Feb 2011 09:31:35 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1297771986.3935.9.camel@jlt3.sipsolutions.net> References: <1297619803-2832-1-git-send-email-njs@pobox.com> <1297619803-2832-5-git-send-email-njs@pobox.com> <1297685871.3785.39.camel@jlt3.sipsolutions.net> <1297771986.3935.9.camel@jlt3.sipsolutions.net> Date: Tue, 15 Feb 2011 09:31:34 -0800 Message-ID: Subject: Re: [PATCH 4/5] iwlwifi: auto-tune tx queue size to minimize latency From: Nathaniel Smith To: Johannes Berg Cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org, wey-yi.w.guy@intel.com, ilw@linux.intel.com Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Feb 15, 2011 at 4:13 AM, Johannes Berg wrote: > On Mon, 2011-02-14 at 13:58 -0800, Nathaniel Smith wrote: >> I don't know. I take it you're imagining a scheme where mac80211 keeps >> a hash table or similar of all packets that have been queued to the >> device, and does its own tx rate estimation and calls start/stop_queue >> as needed? If that works, then it would be lovely. (Heck, it should >> probably go in the generic net layer eventually; ethernet cards have >> the same problem.) > > Well, no, why would it keep a hash table?? The current patch, whenever it queues a packet, stores t = the current time S = the current size of the queue so that later when the TX completes, it can compute (now - t)/S to estimate the per-packet transmission time. I just mean that you'd need somewhere to store this stuff, or else find another algorithm for rate estimation. -- Nathaniel